AUGUSTA, Ga. (AP) — Strong winds and a fall down a staircase by the Masters pre-tournament favorite could change the complexion of the season's first major.

Dustin Johnson, the world's No. 1-ranked golfer, injured his lower back late Wednesday afternoon in what his agent described as a "serious" fall down the staircase at a home he'd rented for the week. Johnson goes off in the last group for Thursday's opening round, but even the late 2:03 p.m. starting time may not give him enough time to recover.

"He landed very hard on his lower back and is now resting, although quite uncomfortably," David Winkle, Johnson's agent said in an email. "He has been advised to remain immobile and begin a regimen of anti-inflammatory medication and icing, with the hope of being able to play tomorrow."

Johnson has won his last three starts. His questionable status further scrambled what was already predicted to be a wild first round.

The weather forecast for the region , socked by powerful storms two of the last three days, calls for cool, overcast skies and steady winds of 20-30 mph, with gusts up to 40 mph. Augusta National can bedevil the world's best in tame conditions. But strong winds make hitting fairways and approach shots even tougher, and if the greens dry out, putting can turn treacherous.

Johnson was at the club earlier in the day to practice before the wave of storms forced Masters officials to close the course. Coincidentally, he predicted earlier in the week that tough conditions could make the leaderboard resemble a game of musical chairs.

"The short game is going to be very important around here because if it's blowing 27 miles an hour, like it's forecasted for, it's going to be tough to hit the greens," Johnson said. "You're going to really have to be careful where you hit it and just try to make pars."

Some other things to watch for at the Masters:

SLAMMING RORY: Only five players have won the career Grand Slam. For the third year in a row, Rory McIlroy has a chance to join the exclusive club. The Masters has been the only major missing from his resume since his victory at the 2014 British Open. Strangely enough, it looked like Augusta was going to provide his first major title six years ago. McIlroy went to the final round with a four-stroke lead, only to post a horrific 80 that included a shot behind a cabin along the 10th fairway.

A NEW DAY: Augusta National at times can favor emotion. Who can forget Ben Crenshaw winning just days after he was a pallbearer at swing coach Harvey Penick's funeral? That might bode well for Australian Jason Day, who wasn't entirely sure he was going to play a few weeks ago when his mother came to America to have surgery for lung cancer. The operation went well and her prognosis suddenly got a whole lot better. "I owe everything to her," Day said.

SPIETH'S COMEBACK: No one was more eager than Jordan Spieth for another shot at the Masters . The young Texan had a five-shot lead going to the back nine on Sunday last year, seemingly a lock for his second straight green jacket. It all fell apart at the par-3 12th, where he dumped two shots in the water and surrendered the lead with a quadruple-bogey 7. "We'll step out and try and get a chance to win on Sunday on the back nine again," Spieth said. "That's all we're asking for. That's it. Just that small little piece."

DEFENDING CHAMP: Danny Willett hasn't been much of a factor since winning the green jacket a year ago with a bogey-free 67 in the final round. His best finish of 2017 is a tie for fifth at the Maybank Classic, an Asian-European Tour event with a weaker field than any tournament played on this side of the Atlantic this year. He's slipped to No. 17 in the world rankings. "You've got to either climb down or stay up there," he said, "and it's incredibly difficult to stay up there all the time."

TIGER WATCH: No need to look for Tiger Woods. The four-time Masters champion is sitting out the tournament for the second year in a row — and third time in the last four years — as he deals with another injury. Woods missed a chance to play on the 20th anniversary of his first major title, a 12-shot runaway at the 1997 Masters that signaled his emergence as the game's dominant player.

Jordan Spieth reacts to a shot by Matt Kuchar on the second hole during a practice round for the Masters golf tournament Wednesday, April 5, 2017, in Augusta, Ga. (AP Photo/David J. Phillip) (Photo: The Associated Press)

The Masters 2017: first round – live!

The tradition of Honorary Starters stretches back to 1963, when 1908 US Open champion Fred McLeod and Jock Hutchinson, winner of the Open Championship in 1921, hit ceremonial drives down Tea Olive. Then played the front nine for a beer a hole. Neither man had ever won the Masters, but each held aloft the Senior PGA Championship during the 1930s when it was played at Augusta National. Since then, the role has been fulfilled in turn by Masters legends Byron Nelson, Gene Sarazen, Sam Snead, Arnold Palmer, Jack Nicklaus and Gary Player.

Last year’s ceremony was bittersweet enough, Nicklaus and Player sending their tee shots away as a frail Palmer looked on from a chair. But the King’s gone now, so this year it’s just the Golden Bear and the Black Knight doing the honours. The 1958, 1960, 1962 and 1964 winner hasn’t been forgotten, though. How could he be? Every patron entering the grounds this morning will receive a special badge commemorating the godfather of modern golf: “I am a member of Arnie’s Army, Est. 1959, April 6, 2017.” Nicklaus and Player wipe away the tears as they gesture towards the heavens, then do their thing. Close your eyes, drift away, and you may be able to hear a third ball landing softly on the fairway.

Welcome, dear Patrons ...

... to our hole-by-hole coverage of the 81st Masters Tournament. Will Danny Willett become only the fourth player in history, after Jack Nicklaus, Nick Faldo and Tiger Woods, to successfully defend his title and pull on his own green jacket? On balance of probability, it’s unlikely. Then again, you’d not have given him much chance of winning last year either, not when Jordan Spieth curled a 25-footer into the cup at 9 on Sunday afternoon for his fourth birdie in a row and a five-shot lead. But look what happened there.

Spieth’s shocking quadruple-bogey meltdown on 12 tends to obscure the steely brilliance with which Willett seized the day. Upon being catapulted to the top of the leader board, he knocked his tee shot at 16 to six feet for birdie, then bumped an 80-foot chip to inches from the back of 17 for a street-fighting par that, in retrospect, sealed the deal with Spieth momentarily threatening to launch a comeback. The initial opportunity might have been gifted to Willett, but nothing else was handed on a plate: he still had to close it out, and under immense pressure did so with aplomb. Top class.

Willett’s poor form this season suggests a rerun is extremely unlikely, but fear of failure shouldn’t colour his judgement this week. Should the worst happen, and he misses the cut as defending champion, he’ll only be following in the footsteps of some other great names. Hey, if it can happen to Nicklaus, Faldo, Ben Crenshaw or José-María Olazábal, it can happen to anyone. Hell, it happened to Seve twice. Seve! Twice!

Plenty of folk are desperate to follow in Willett’s footsteps. Spieth, for a start: last year’s shenanigans around Amen Corner make it easy to forget the brilliant young Texan still finished in a tie for second. In his other two appearances, he’s tied again for second and won the damn thing. He loves this course, is blessed with the necessary calm constitution - hell, after his capitulation at 10, 11 and 12 last year he regrouped immediately to birdie 13 and 15 - and in a supposedly quiet year he’s already won a couple of times on Tour. Nobody who saw him drape the green jacket over Willett’s shoulders last year, wearing a genuinely warm and sporting smile despite raging inner turmoil, would begrudge him the favour returned.

Dustin Johnson has long been the favourite. He’s the world number one, the reigning US Open champion, the current holder of three of the four WGC titles, and on a run of three Tour victories in a row. Set against that is his relatively poor record at Augusta National - he’s never seriously threatened on Sunday, with a best-place tie for fourth last year - and the fact that no favourite has won here since Tiger in 2005. Oh, and the possibility of one of those trademark major meltdowns. If he were to throw away a winning position here, he’d complete a meltdown slam, having in the past found increasingly esoteric ways to pass up wins at the US Open, PGA and Open. But does he do that sort of thing these days? Possibly not... ah hold on, he’s fallen down the stairs. What a merry puddle. An injured back puts his very participation in doubt! We’ll keep you posted.

As for the others, Rory McIlroy is desperate to complete his career grand slam and banish the ghouls of 2011. His length and high ball flight will give him an advantage in damp conditions; it’s all down to his putter, then, never the most dependable of clubs. Softer greens will help. Jason Day has knocked on the door often enough at Augusta, with second, third and 10th-placed finishes already to his credit; his mental state is the only question mark, the young man understandably preoccupied with the health of his mum. Henrik Stenson has by contrast never seriously contested a Masters; now he’s got the major monkey off his shoulder, could he be ready for a tilt?

Justin Rose, Rickie Fowler, Hideki Matsuyama, Louis Oosthuizen, Lee Westwood and Paul Casey have all come close in recent years. Former champions Phil Mickelson, Adam Scott, Charl Schwartzel, Zach Johnson and Bubba Watson can never be ruled out. Meanwhile Justin Thomas is perhaps the more likely of the two bright young things, partly because he’s won three times on tour already this season, partly because the much-fancied Jon Rahm is playing his first Masters and only one man (Fuzzy Zoeller in 1979) has ever won on debut, so history is not the Spaniard’s friend. (Well, Horton Smith and Gene Sarazen won on debut too, in 1934 and 1935, but those were the first two tournaments, which kind of compromises the feat.) Still, you wouldn’t put it past Rahm. Look how far he hits it!

And then there’s Brandt Snedeker, Mark Leishman, Bill Haas, Thomas Pieters, Matthew Fitzpatrick, Tyrrell Hatton, Adam Hadwin, Brooks Koepka, Daniel Berger, Tommy Fleetwood, Serg... but it’s probably best to stop now, we could be here all day. Let’s just agree the possibilities are infinite. So pour yourself an iced tea, spread some pimento cheese onto a cracker, and settle down for four days of sporting bliss. A severe fever is taking hold; won’t somebody please call Dr Golf?!!

We’ll get this hole-by-hole report underway soon. Meanwhile, here are the first tee times, with local time followed by British time in brackets, and the amateurs asterisked.